Agreed, separate powder and feed drives will be in any prototype I make.
Only after I have convinced myself that I can run them fully in parallel will I move to a single drive model.
I'm going to give the ink + halogen lamp idea a few more goes, but I am beginning to think that a thermal head (like in a receipt printer) may be better for sugar printing.
I'll leave BrundleFab as-is if I decide to get into the plaster powder arena - it should work fine for that.
/me starts looking up more Tr threaded rods on EBay....